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Build concrete core filled masonry block arches without a template See also: Masonry Arch Header Cut and Placement Calculator

An arch has 2 identical sets of cuts
(left and right sides). A bulls-eye (circle) has 4.

How it works When the wall is core filled, the membrane (flashing) around the arch line stops the concrete. Remove off-cuts and extra blocks to reveal the arch.

Height In
Cut all the blocks before construction. The cut blocks (all halves) that form the arch are numbered sequentially, with off-cuts numbered identically. Take the opening to spring height, then using a standard horizontal head support, go across the head, laying each cut in its place, its matching off-cut on top, with a membrane (aluminum flashing is ideal) between the two. Lay the cut, place the flashing on top of the cut line and lay the off-cut to lock membrane in place.
Use overlapping lengths of thick, strong (aluminum) flashing about 3 feet long so the flashing doesn't get in your way.

Concrete block arch diagram

Circular Raking Walls with Arch or Bullseye You can combine this Templateless Arch System with the Circular Wall System to easily build curved or circular (and raking) walls with arches or bulls-eyes. It's easy! If you'd like more detailed info on this, please contact us.

DON'T BREATH THE DUST If you're cutting blocks, concrete, stone or ANYTHING and there's DUST - DON'T TAKE THE RISK
Don't cut it, or cut it wet so there's NO DUST - Silicosis Sucks
And if you're cutting wet, wear a mask - there's dust in the spray too!

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